1. Field of the Invention
The present invention relates to spacecraft. More particularly, the present invention relates to a satellite having a plurality of flat panels that are deployable to a precise coplanarity wherein the front surfaces of the panels are unmarred by protruding hardware.
2. Description of the Related Art
Space satellites often include a foldable panel array comprised of a plurality of flat panels, such as solar panels or antenna panels. The individual panels each have a planar front or active surface upon which planar functional components, such as solar cells, reflectors, or antenna elements, are mounted. The active surfaces of the panels are desirably maintained smooth and unmarred by any projections, which tend to degrade the performance of the panels. Toward this end, any hardware devices, such as structural supports and hinge mechanisms, are desirably mounted on a rear surface of the panels so that they do not interfere with the planarity of the active surfaces.
The panel array may be maintained in a stowed or folded state wherein the individual panels are folded over one another in an accordion-like fashion. In the folded state, the surface of one panel is juxtaposed with a surface of an adjacent panel so that the panels are stacked atop one another so that the panel array consumes less space. The panel array is preferably maintained in the folded state prior to use and also during launch of the spacecraft in order to conserve precious cargo space within the spacecraft launch vehicle.
The panel array transitions to a deployed or extended state after the satellite reaches orbit. In the deployed state, the individual panels are disposed in an edge-to-edge fashion such that the active surfaces of the panels are aligned in a common plane. The active surfaces of the individual panels thereby collectively form an enlarged active surface for the panel array. During the transition from the folded state to the deployed state, the individual panels are each typically rotated outward using a hinge assembly that is disposed between adjacent panels.
Unfortunately, current hinge hardware tends to interfere with the performance of the active surfaces of the panel array. Current hinge assemblies typically comprise pin hinges that define a fixed axis of rotation for the panels. Consequently, depending on the manner in which the panel array is folded, a portion of the pin assembly protrudes upwardly from the active surface of the panels after the panels have been deployed. As mentioned, such protrusions or irregularities in the active surface of the panel array degrades the performance of the array.
There is therefore a need for a spacecraft panel array that may be deployed to an extended state wherein the coplanarity of the active surfaces is unmarred by hardware such as hinge assemblies. Additionally, the panels are desirably held tightly together in the extended state, such as through the application of a high preload that maintains the structural continuity and rigidity of the panel array.
The aforementioned needs are satisfied by the present invention, which comprises a spacecraft having a panel array comprised of a plurality of panels. The panel array is movable between a folded state and a deployed or extended state. In the folded state, the panels are folded over one another in a juxtaposed relationship. In the extended state, the panels are aligned edge-to-edge such that the front or active surfaces of the panels are disposed within a common plane. The panel array includes at least one hinge assembly disposed between each of the panels in the array. The hinge assemblies are configured to rotate the panel array from the folded state to the extended state. Advantageously, the hinge assemblies do not intersect any portion of the active surface of the array when the array is in the extended state. The hinge assemblies therefore do not interfere with the performance of the active surface.
The panel array also preferably includes a latching mechanism for rigidly securing the panel array in the extended state and maintaining the coplanarity of the panels when extended. The latching mechanism comprises at least one latch on one panel and a hook on an adjacent panel. The latch couples with the hook after the array has been extended to thereby exert a panel-to-panel preload that establishes structural continuity between the panels and prevents the array from moving to the folded position after deployment. In a preferred embodiment, a plurality of latches are disposed in an aligned relationship with a single actuator coupled to each of the latches. The single actuator is desirably configured to transition each of the latching members from a cocked position to a latched position so that each of the latches simultaneously couples with each of the hooks.
In one aspect of the invention, there is disclosed a hinge mechanism for deploying a system of satellite panels comprised of at least a first panel and a second panel. The hinge preferably comprises a pair of arms each rotatably coupled at opposite ends to the first panel and the second panel. The pair of arms are configured to apply a force to the first and second panels so that the first panel rotates relative to the second panel about a non-fixed axis of rotation. The hinge mechanism additionally comprises at least two latch mechanisms coupling the first panel to the second panel. The latch mechanisms are each movable to a locked state wherein the latch mechanisms secure the first and second panels in a deployed position. An actuator is coupled to each of the latch mechanisms and configured to move the latch mechanisms to the locked state.
Another aspect of the invention relates to a deployable mechanism for use in space. The mechanism comprises at least a first panel defining a front surface and a rear surface and at least a second panel defining a front surface and a rear surface. The first and second panels are rotatably coupled to one another and moveable between a first position wherein the front surfaces are juxtaposed and a second position wherein the front surfaces are aligned within a common plane. The mechanism additionally comprises at least one hinge assembly rotatably coupling the first panel to the second panel. The hinge assembly is positioned entirely outside the common plane when the first and second panels are in the second position. Desirably, a motor is drivingly coupled to the hinge assembly.